Cow

A cow and her calf were not to be killed on the same day (Lev.
22:28; Ex. 23:19; Deut. 22:6, 7). The reason for this enactment
is not given. A state of great poverty is described in the words
of Isa. 7:21-25, where, instead of possessing great resources, a
man shall depend for the subsistence of himself and his family
on what a single cow and two sheep could yield.